Lateral interbody fusion devices, systems and methods

ABSTRACT

According to some embodiments, a method of inserting a lateral implant within an intervertebral space defined between an upper vertebral member and a lower vertebral member includes creating a lateral passage through a subject in order to provide minimally invasive access to the intervertebral space, at least partially clearing out native tissue of the subject within and/or near the intervertebral space, positioning a base plate within the intervertebral space, wherein the base plate comprise an upper base plate and a lower base plate and advancing an implant between the upper base plate and the lower base plate so that the implant is urged into the intervertebral space and the upper vertebral member is distracted relative to the lower vertebral member.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application No. 61/786,160, filed Mar. 14, 2013, the entirety of which is hereby incorporated by reference herein.

BACKGROUND

Field

This application relates generally to devices, systems and methods for the treatment of the spine, and more specifically, to spinal implants and related tools, systems and methods.

Description of the Related Art

Surgical approaches to the intervertebral space are utilized for a variety of indications and purposes, such as, for example, biopsy (e.g., for evaluation of possible infection, other pathology, etc.), discectomy (e.g., for decompression of nerve roots, to prepare for subsequent fusion procedures, etc.), disc height restoration or deformity correction, disc replacement or repair (e.g., annular repair), discogram, gene therapy and/or other procedures or treatments.

Various approaches are currently used to access the interbody or intervertebral space of a patient's thoracic, lumbar and sacral spine. These include anterior approaches (ALIF) (e.g., open, mini-open retroperitoneal, etc.), lateral approaches (e.g., costotranversectomy, extreme lateral, etc.), posterolateral approaches (e.g., posterior lumbar interbody fusion (PLIF), transforaminal lumbar interbody fusion (TLIF), etc.) and axial approaches (e.g., axial lumbar interbody fusion). Further, many minimally invasive and percutaneous approaches rely on radiographic landmarks with or without direct view to access a targeted interbody space. In addition, many, if not all, of these currently used approaches require violation of the disc annulus to access the disc space.

Fusion surgery of the thoracic, lumbar and sacral spine is often performed for a variety of indications, including degenerative joint disease, deformity, instability and/or the like. Typically, traditional fusion approaches involve relatively large, open incisions performed under direct vision. Minimally invasive surgical techniques and corresponding surgical implants have become more popular in an attempt to reduce morbidity and generally improve outcomes. Multiple variations of percutaneous systems (e.g., pedicle screw and rod systems, facet screw systems, etc.) have been developed. Such systems can allow for instrumentation placement with fluoroscopic guidance (e.g., using radiographically recognizable body landmarks) and/or other imaging technologies. Current fusion techniques, including those that utilize open and minimally invasive approaches, often require direct visualization. However, such techniques typically involve traversing spaces that are occupied by neural elements. Thus, these neural elements need to be retracted or otherwise moved during the execution of spinal procedures that precede implantation (e.g., annulotomy, discectomy, disc space and/or vertebral endplate preparation, etc.). Retraction of sensitive neural elements can also be required during the delivery of an implant to the spine.

These approaches typically require contact and retraction of nerve roots and/or sensitive visceral organs, blood vessels and/or other sensitive portions of the anatomy. Contact and retraction of these structures can place them at risk, thereby increasing the likelihood of complications and damage to a patient. Accordingly, a need exists for improved approaches for spinal fusion and/or access to intervertebral spaces.

SUMMARY

According to some embodiments, a method of inserting a lateral implant within an intervertebral space defined between an upper vertebral member and a lower vertebral member includes creating a lateral passage through a subject in order to provide minimally invasive access to the intervertebral space, at least partially clearing out native tissue of the subject within and/or near the intervertebral space, positioning a base plate within the intervertebral space, wherein the base plate comprise an upper base plate and a lower base plate and advancing an implant between the upper base plate and the lower base plate so that the implant is urged into the intervertebral space and the upper vertebral member is distracted relative to the lower vertebral member.

According to some embodiments, advancing an implant between the upper and lower base plates comprises using a mechanical device (e.g., a threaded-system using a rotable handle to advance a rod or other actuator, manual or mechanically-assisted device, etc.). In some embodiments, the implant comprises at least one groove and at least one of the upper base plate member and the lower base plate member comprises at least one protruding feature, the at least one groove being configured to align and move relative to the at least one protruding feature. In some embodiments, the implant is delivered through the base plate using a rail or other alignment system. In some embodiments, the implant comprises at least one of PEEK, titanium and/or the like. In some embodiments, the base plate comprises titanium, stainless steel or another medically-acceptable metal or alloy.

According to some embodiments, the method further includes securing at least one screw (e.g., 1, 2, 3, 4, more than 4, etc.) through an opening of the implant after the implant has been properly secured within the intervertebral space. In one embodiment, the screw also passes through at least a portion of the upper or lower base plate member and/or the upper or lower vertebra.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages of the present application are described with reference to drawings of certain embodiments, which are intended to illustrate, but not to limit, the present inventions. It is to be understood that these drawings are for the purpose of illustrating the various concepts disclosed herein and may not be to scale.

FIG. 1 schematically illustrates one embodiment of a spinal implant system with the implant not positioned within the target intervertebral space;

FIG. 2 illustrates the system of FIG. 1 with the implant positioned between the base plate members and implanted within the intervertebral space;

FIGS. 3A and 3B illustrate various views of a base plate of an implant system according to one embodiment;

FIG. 4 illustrates a side view of a spinal implant system according to one embodiment;

FIGS. 5A-5C illustrate various views of one embodiment of a base plate for use in a spinal implant system;

FIGS. 6A and 6B illustrate various views of one embodiment of an implant configured for use in a spinal implant system;

FIG. 7A illustrates one embodiment of a base plate configured for use in a spinal implant system;

FIG. 7B illustrates one embodiment of an implant configured to be used together with the base plate of FIG. 7A;

FIGS. 8A-8C illustrate various time-sequential side views during a spinal implant procedure according to one embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A variety of examples described below illustrate various configurations that may be employed to achieve desired improvements. The particular embodiments and examples are only illustrative and not intended in any way to restrict the general concepts presented herein and the various aspects and features of such concepts.

According to some embodiments, the present application discloses various devices, systems and methods for accessing the intervertebral or interbody space of a patient's spine and/or performing certain procedures related to spinal fusion using minimally invasive surgery (MIS) techniques. As discussed in greater detail herein, the intervertebral or interbody space of the targeted portion of the patient's spine is accessed and/or treated minimally invasively using, at least in some embodiments, a lateral approach. The terms “intervertebral space” and “interbody space” are used interchangeably herein, and generally refer to the space, gap or region between adjacent vertebral members. By way of example, as illustrated in FIG. 1, the intervertebral space 14 between adjacent vertebrae 10, 12 can be accessed using one or more lateral openings or passages created laterally through the subject's anatomy (e.g., using one or more access device, such as, retractors, dilators, etc.). In some embodiments, such openings or passages are created, accessed and/or otherwise use using MIS techniques or procedures.

FIG. 1 schematically illustrates one embodiment of a spinal fusion or stabilization system 50. As shown, the system 50 can include upper and lower plates 300 or other members that are positioned along the endplates of the upper and lower vertebral members 10, 12. In some embodiments, the plates 300 generally extend across the entire or substantially the entire width of the vertebrae 10, 12. In some embodiments, the plates 300 are the same length or substantially the same length as the spinal implant 200 that will be delivered between the plates 300 and into the intervertebral space 14. For example, the plates 300 and/or the implant 200 can be approximately 40 to 60 mm long (e.g., 40, 45, 50, 55, 60 mm, lengths between the foregoing ranges, etc.). In other embodiments, however, the length of the implant is greater than 60 mm or less than 40 mm, as desired or required.

In some embodiments, once the plates have been properly positioned within the target intervertebral space 14, the implant 200 can be delivered (e.g., laterally) between the upper and lower plates or other members 300. The delivery of the implant 200 between the plates 300 can be performed with or without the use of a mechanical delivery tool (e.g., by using a threaded delivery device or other device providing for mechanical advantage, etc.). Regardless of the exact manner in which the implant 200 is advanced into the intervertebral space 14, the upper and lower plates 300 can provide one or more advantages or benefits. For example, the use of the plates 300 can help distribute forces and moments along a larger surface area. This is schematically and generally illustrated by the force distribution diagram F in FIG. 2. Accordingly, the likelihood of potentially damaging localized forces, moments and/or other stresses on a particular portion or area of the adjacent vertebrae 10, 12 can be reduced or eliminated.

Further, in some embodiments, the use of the upper and lower plates 300 can facilitate the delivery of the implant 200 within the target interbody space with greater ease and less resistance. As a result, the endplates and other portions of the adjacent vertebrae 10, 12 can be protected against shearing, fractures and/or other damage. This can be especially important when the implant 100 causes distraction (e.g.,. separation or opening) of a collapsed or partially collapsed interbody space 14, as represented by the arrows 16 in FIG. 2.

As discussed herein, one or both sides of the upper and/or lower plates can include spikes, teeth, other protruding members and/or other engagement features. For example, if such engagement features are positioned along the top of the upper plate or the bottom of the lower plate, the engagement features can be advanced into the adjacent endplate(s) as the implant 200 is moved between the plates 300. This can help secure the plates to the adjacent vertebrae 10, 12. In some embodiments, engagement features can be positioned along the opposite surfaces of the plates (e.g., along the bottom of the upper plate and/or along the top of the lower plate). Such engagement features can help prevent or reduce the likelihood of relative movement between the implant 200 and the plates 300 following implantation. As discuss in greater detail herein, the plates can include one or more other features, such as, for example, rails or guiding members (e.g., to assist in moving the implant more easily and more predictably between the plates), tabs or other portions configured to receive one or more screws or other fasteners (e.g., to further secure the system 100 to the spine after delivery into the intervertebral space) and/or the like.

FIGS. 3A and 3B illustrate different views of one embodiment of plates (e.g., base plates) 300 configured for use in a lateral spinal fusion system. As shown, the base plates 300 can include upper and lower plates 310, 314. The base plates 300 can be shaped, sized and configured to span across an entire width of the subject's vertebrae 10, 12. In other embodiments, the base plates 300 extend beyond one or more side of the vertebral periphery or do not extend to the lateral edge of the vertebrae (e.g., are short by a certain clearance distance from one or more lateral edges of the vertebrae). As shown in FIG. 3A, the plate members 310, 314 can include one or more protruding members 320 that extend toward each other (e.g., toward the intervertebral space). Such protruding members can be fixed or movable. For example, in some embodiments, the protruding members 320 are deployable (e.g., before, during or after advancement of an implant between the base plates 300).

With continued reference to FIG. 3A, a system can include a guiding assembly 500 that can be strategically positioned along one of the lateral ends of the targeted intervertebral space. The guiding assembly 500 can include an alignment device 510 that may comprise one or more alignment components 514, 516. Regardless of its exact configuration and design, the alignment device can advantageously permit a surgeon or other practitioner to accurately position the guiding assembly 500 for the subsequent delivery of an implant therethrough and between the base plates 300. As shown in FIG. 3A, the alignment components 514, 516 and/or one or more other portions or components of the assembly can include a flange or other abutment or securement portion 518. Such a flange 518 can be fixedly or movable positioned along the adjacent vertebrae 10, 12 of the subject to ensure proper alignment into the targeted intervertebral space.

As illustrated in FIG. 4, an implant 200 can be delivered between the base plates 300 and into the intervertebral space using a mechanical advancement device. Therefore, in some embodiments, the guiding assembly 500 can advantageously comprise a mechanical advancement device or feature. For example, in FIG. 4, the guiding assembly comprises a threaded delivery portion that is configured to advance an implant 200 between the base plate members 310, 314 by turning a rotable handle or other advancement tool. As a user rotates the handle 520, a rod 522 or other actuator is moved forwardly (e.g., distally) in the direction of the implant 200. The implant 200 can be directly or indirectly coupled to the actuator 522 via one or more coupling or other detachable connections 526, as desired or required. As the rod is advanced distally, the implant (e.g., lateral cage) can be guided between the base plate members 310, 314 and into the intervertebral space. Consequently, the base plate members 310, 314 separate and are urged toward the adjacent endplates of the vertebrae. In some embodiments, as illustrated schematically in FIG. 4, the implant can include a taper (e.g., bullet design) along its distal end to facilitate initial entry and subsequent distraction and separation of the base plate 300.

With continued reference to FIG. 4, the guiding assembly 500 can include one or more structures 510 that ensure that the implant stays within the guiding assembly 500 and aligned with the intervertebral space during advancement between the plates. Such structure 510 can, for example, help reduce any deflection or misdirection of the implant's leading end during distal delivery to the intervertebral space, especially when relatively high forces are being exerted on the implant (e.g.,. that may otherwise cause the implant to move our of alignment with the base plates). In some embodiments, the implant 200, the base plates 300 and/or any other portion of the system can include rails or other alignment features that further help maintain a proper alignment of the implant during advancement between a subject's vertebrae.

FIGS. 5A-5C illustrate various views of another system comprising base plates 300 for receiving a spinal implant. As shown, an alignment device 510′ can be positioned relative to one or more of the adjacent vertebrae 10, 12 more securely. For example, one or more screws S or other fasteners can be used to secure one or more portions of the alignment device to the upper and/or lower vertebral members of the subject. In some embodiments, the alignment devices 510′ comprise one or more flanges or plates P through which the screws S or other fasteners can be placed. Once the alignment device 510′ has been secured to the subject, the implant can be delivered between the base plate members 310, 314. The alignment device 510′, base plate 300 and/or other portions of the system can be left in place after the implant has been secured between the subject's vertebrae. In other embodiments, however, one or more components of the system (e.g., base plate 300, screws, etc.) can be left in place after implantation, and in some instances, may help reinforce or otherwise benefit the treated area.

One embodiment of an implant 200 that can be used with the spinal systems disclosed herein is illustrated in FIGS. 6A and 6B. As best shown in the top view of FIG. 6B, the implant 200 can include one or more open regions or chambers 210 for holding a grafting material. In addition, the implant can include one or more grooves 220 or other recesses along its anterior and/or posterior walls. In some embodiments, such grooves 220 or other features can align and mate with corresponding rails, protrusions or features of the base plate 300. Accordingly, the grooves, rails and/or other features can help safely, accurately and predictably move the implant 200 into the target intervertebral space (e.g., between adjacent base plate members).

In some embodiments, the implant comprises PEEK, titanium or other acceptable materials. For example, in some embodiments, the implant 200 comprises a metal edge plate 226 through which one or more screws (not shown in FIGS. 6A and 6B) can be subsequently delivered to secure the implant 200 to one or more vertebrae. In some arrangements, the plate 226, which can be positioned along the proximal end of the implant 200, comprises titanium or other acceptable metal or alloy.

FIG. 7A illustrates a side view of one embodiment of a base plate 300 comprising upper and lower plate members 310, 314. As shown, the base plate members 310, 314 can include one or more protruding members 320. Such protruding members 320 can include tabs, bumps, spikes, other sharp, smooth and/or rounded features or members and/or the like. In some embodiments, the protruding members 310, 314 can be fixed (e.g., non-movable, non-deployable, etc.) and/or movable (e.g., selectively retractable, deployable, etc.). For example, in some embodiments, the protruding members 320 of the upper and/or lower plate members 310, 314 are deployable using a mechanical connection, a temperature change and/or using some other mechanism of action, device or method.

FIG. 7B illustrates a top view of one embodiment of an implant 200 that is configured to be used with the base plate 300 of FIG. 7A. Specifically, as shown, the implant 200 can include one or more grooves, holes, recesses or other openings 240 that are shaped, sized and otherwise configured to receive corresponding protruding members 320 of the base plate 300. In some embodiments, the protruding members 320′ of the base plate 300 include a curved leading edge in order to permit the groove 240 of the implant 200 to only temporarily engage the member 320′ as the implant is advanced into the target intervertebral space. Thus, the protruding members can sequentially engage and disengage a groove on the implant (e.g., in a ratcheting manner). In some embodiments, the implant can only be permitted to be advanced in one direction (e.g., distally). Such an embodiment can be helpful when using base plates 300 that have fixed protruding members 320. In embodiments comprising deployable protruding members, the need for such ratcheting system (e.g., that permits movement in at least one direction) may not be needed, as the protruding members 320 can be selectively deployed only when the implant is properly positioned between the base plate members.

In some embodiments, the use of protruding members and corresponding grooves or other recesses can help with guiding an implant 200 between adjacent base plate members (e.g. during delivery). Such embodiments can also assist in securely maintaining the implant in its implanted positioned following delivery of the implant in the target intervertebral space.

As illustrated schematically in FIGS. 8A-8C, a lateral implant device in accordance with the various embodiments disclosed herein, can be delivered to the target intervertebral space minimally invasively (e.g., through one or more tissue dilations or other openings). As discussed in greater detail herein, once the base plate 300 has been properly positioned between the subject's vertebrae 10, 12, a guiding assembly 500 can be positioned through a dilator or other access opening and in general alignment with the targeted intervertebral space. The implant can be advanced using a mechanical device (as illustrated in FIG. 8A) and/or using some other method or device. Further, the implant and base plate can include one or more features or members (e.g., rails, grooves, etc.) to assist in accurately moving the implant in the desired anatomical location of the subject's spine. Once the implant has been advanced between the base plate members 310, 314 and properly within the intervertebral space, the guiding assembly 500 can be removed.

With reference to FIG. 8B, in some embodiments, a screwdriver or other mechanical device 600 can be delivered through a dilator, cannula or other access device C to advance one or more screws S or other fasteners through corresponding openings along the proximal end of the implant 200. Therefore, the position of the implant 200 relative to the subject's spine can be safely and firmly maintained, as shown in FIG. 8C. The screws S can be routed through the implant, the base plate and/or the vertebra, as desired or required. However, in other embodiments, the use of screws S or other fasteners is not needed or required to maintain the implanted implant between the base plate members and the adjacent vertebrae. In some embodiments, a total of four fixation screws are positioned through the proximal end of the implanted implant (e.g., two above and two below). In other embodiments, more or fewer screws or other fasteners can be used, as desired or required.

In order to remove disk material, cartilage, endplate or other vertebral tissue and/or native tissue of a subject during an implantation procedure, a surgeon or other practitioner can use any of the rasping or other tissue cutting devices and methods disclosed in U.S. patent application Ser. No. 13/422,816, titled TRANSPEDICULAR ACCESS TO INTERVERTEBRAL SPACES AND RELATED SPINAL FUSION SYSTEMS AND METHODS, filed Mar. 16, 2012 and published as U.S. Publ. No. 2012/0265250 on Oct. 18, 2012, and U.S. Provisional Patent Application No. 61/783,839, titled DEVICES AND METHODS FOR TRANSPEDICULAR STABILIZATION OF THE SPINE and filed on Mar. 14, 2013, the entireties of both of which are hereby incorporated by reference herein and made a part of the present application.

To assist in the description of the disclosed embodiments, words such as upward, upper, bottom, downward, lower, rear, front, vertical, horizontal, upstream, downstream have been used above to describe different embodiments and/or the accompanying figures. It will be appreciated, however, that the different embodiments, whether illustrated or not, can be located and oriented in a variety of desired positions.

Although the subject matter provided in this application has been disclosed in the context of certain specific embodiments and examples, it will be understood by those skilled in the art that the inventions disclosed in this application extend beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the subject matter disclosed herein and obvious modifications and equivalents thereof. In addition, while a number of variations of the inventions have been shown and described in detail, other modifications, which are within the scope of these inventions, will be readily apparent to those of skill in the art based upon this disclosure. It is also contemplated that various combinations or subcombinations of the specific features and aspects of the embodiments may be made and still fall within the scope of the inventions disclosed herein. Accordingly, it should be understood that various features and aspects of the disclosed embodiments can be combine with or substituted for one another in order to form varying modes of the disclosed inventions. Thus, it is intended that the scope of the subject matter provided in the present application should not be limited by the particular disclosed embodiments described above, but should be determined only by a fair reading of the claims that follow. 

What is claimed is:
 1. A method of inserting an implant system within an intervertebral space defined between an upper vertebral member and a lower vertebral member, the method comprising: removing at least some native tissue of the subject from or adjacent to the intervertebral space; positioning an upper base plate and a lower base plate of the implant system within the intervertebral space, wherein the upper base plate is separate from the lower base plate; and advancing an implant of the implant system between the upper base plate and the lower base plate so the implant is urged into the intervertebral space, wherein advancing the implant between the upper and lower base plates separates the upper base plate relative to the lower base plate along an entire length of the implant and urges the upper base plate toward the upper vertebral member and the lower base plate toward the lower vertebral member; wherein advancing the implant between the upper and lower base plates helps to distribute forces and moments imparted by the implant, thereby reducing a likelihood of damage to the adjacent upper and lower vertebral members; wherein at least one of the upper base plate and the lower base plate comprises a plurality of engagement features; and wherein the engagement features are configured to be mechanically movable and deployable when the implant is positioned between the upper and lower base plates.
 2. The method of claim 1, wherein the implant comprises at least one chamber configured to hold a grafting material.
 3. The method of claim 1, wherein the implant comprises a single implant configured to contact both the upper base plate and the lower plate during and after advancement between the upper and lower base plates.
 4. The method of claim 1, wherein the implant is configured to simultaneously contact the upper base plate and the lower plate during and after advancement between the upper and lower base plates.
 5. The method of claim 1, wherein the upper and lower base plates are the same length or substantially the same length as the implant.
 6. The method of claim 1, wherein advancing an implant between the upper and lower base plates comprises using an advancement tool that provides mechanical advantage.
 7. The method of claim 6, wherein the advancement tool comprises a threaded mechanical device.
 8. The method of claim 1, wherein the engagement features comprise tabs, bumps, spikes, other sharp features or members or rounded features or members.
 9. The method of claim 1, wherein the implant and the upper and lower base plates comprise rails or other alignment features to help maintain a proper alignment of the implant relative to the upper and lower base plates when advancing the implant between the upper and lower base plates.
 10. The method of claim 9, wherein the implant comprises at least one protrusion or rail that is configured to align and mate with at least one corresponding rail or protrusion of at least one of the upper base plate and the lower base plate.
 11. The method of claim 1, wherein the implant is advanced to the intervertebral space using an alignment device, the alignment device comprising upper and lower alignment components through which the implant is moved toward the intervertebral space.
 12. A method of inserting an implant system within an intervertebral space defined between an upper vertebral member and a lower vertebral member, the method comprising: accessing the intervertebral space; positioning an upper base plate and a lower base plate of the implant system within the intervertebral space, wherein the upper base plate is separate from the lower base plate; and advancing an implant of the implant system between the upper base plate and the lower base plate so the implant is urged into the intervertebral space, wherein advancing the implant between the upper and lower base plates separates the upper base plate relative to the lower base plate along an entire length of the implant; wherein advancing the implant between the upper and lower base plates helps to distribute forces and moments imparted by the implant, thereby reducing a likelihood of damage to the adjacent upper and lower vertebral members; wherein at least one of the upper base plate and the lower base plate comprises a plurality of engagement features, wherein the engagement features are configured to advance into an endplate of the upper or lower vertebral member when the implant is advanced between the upper and lower base plates; and wherein the engagement features are configured to be movable when the implant is positioned between the upper and lower base plates.
 13. The method of claim 12, wherein the implant comprises at least one chamber configured to hold a grafting material.
 14. The method of claim 12, wherein the implant comprises a single implant configured to contact both the upper base plate and the lower plate during and after advancement between the upper and lower base plates.
 15. The method of claim 12, wherein the implant is configured to simultaneously contact the upper base plate and the lower plate during and after advancement between the upper and lower base plates.
 16. The method of claim 12, wherein the upper and lower base plates are the same length or substantially the same length as the implant.
 17. The method of claim 12, wherein advancing an implant between the upper and lower base plates comprises using an advancement tool that provides mechanical advantage.
 18. The method of claim 12, wherein the engagement features comprise at least one of the following: a tab, a bump, a spike, a sharp feature or member, a smooth feature or member and a rounded feature or member.
 19. A method of inserting an implant system within an intervertebral space defined between an upper vertebral member and a lower vertebral member, the method comprising: accessing the intervertebral space; positioning an upper base plate and a lower base plate of the implant system within the intervertebral space, wherein the upper base plate is separate from the lower base plate; and advancing a distal end of an implant of the implant system between the upper base plate and the lower base plate so the implant is urged into the intervertebral space, wherein advancing the implant between the upper and lower base plates separates the upper base plate relative to the lower base plate along an entire length of the implant; wherein advancing the implant between the upper and lower base plates helps to distribute forces and moments imparted by the implant, thereby reducing a likelihood of damage to the adjacent upper and lower vertebral members; and wherein the implant comprises at least one chamber configured to hold a grafting material, the at least one chamber being open and accessible during and after implantation of the implant along a proximal end of the implant; and moving a plurality of engagement features of at least one of the upper base plate and the lower base plate at least to an adjacent vertebral member, wherein the engagement features are deployed when the implant is advanced between the upper and lower base plates.
 20. The method of claim 19, wherein the engagement features comprise at least one of the following: a tab, a bump, a spike, a sharp feature or member, a smooth feature or member and a rounded feature or member. 